Over 150,000 amputations occur in the United States annually. Amputations are rising in frequency due to diabetes and peripheral vascular disease. The transtibial level of amputation is the most frequently performed.
A transtibial amputation is an amputation of the lower limb below the knee. A transtibial prosthesis is an artificial limb that replaces the portion of the leg below the knee that is missing. The shape of the residual limb varies for each individual and generally requires a custom-fitted prosthesis. A custom-fitted prosthesis that is comfortable is difficult to fabricate and is costly.
The transfemoral (above knee) level of amputation is less common than the below knee (transtibial) level of limb loss, but results in the highest level of gait dysfunction and disability. Further, the transfemoral level is difficult to fit with a prosthetic socket due to redundant soft tissues and variable lengths and sizes of the residual limb.
A transfemoral prosthesis is an artificial limb that replaces the portion of the leg above the knee that is missing. The shape of the residual limb varies for each individual and generally requires a custom-fitted prosthesis. A comfortable custom-fitted prosthesis is difficult to fabricate and costly to provide using conventional manufacturing techniques.
The initial cost of a conventional prosthesis for a transtibial amputee typically ranges from about $6,000 to about $14,000. In addition, there are additional costs to ensure the comfort and functionality of the device.
The initial cost of a conventional prosthesis for a transfemoral amputee typically ranges from $10,000 to $20,000 depending upon the components used and the difficulty in fitting the individual. In addition, there are additional costs to ensure the comfort and functionality of the device including replacement or revision of the socket.
Insurance coverage of such prosthetic devices is variable across insurers and has often impeded prescription and availability of high quality devices even for amputees with insurance coverage. The uninsured often go without comfortable prosthetic devices for long periods of time before public insurance enables them to receive a functional prosthesis.
The present state of prosthesis fabrication often requires three or more visits to the prosthetist and there are multiple steps in the fabrication process. First, a cast mold of the residual limb is made and a positive cast that resembles the residual limb is generated. Then, a prosthetic socket is built to custom-fit over the positive cast. Sometimes a check or temporary socket is made to insure a better fit. Typical fabrication techniques require specialized facilities. Generally, the final prosthesis requires post-fabrication adjustments as the residual limb tissue changes over time.
Recent advancements have been made in the field of prosthetic devices. However, devices such as computerized knee mechanisms and energy storing feet are costly and beyond the economic means of many prosthetic users, particularly those in nations outside the United States.
Attempts have been made in the prior art to develop prosthesis systems that can be globally manufactured and distributed. These prosthesis systems, however, have several limitations. They are difficult to fabricate and require specialized facilities for initial manufacturing (e.g., casting) and subsequent adjustments. These systems all require expertise and consulting support that is not widely available. In particular, the socket (i.e., the portion of the prosthesis into which the residual limb fits), socket attachment, and alignment aspects of the device seem to be a common problematic area of development.
It is desirable to create a prosthetic device which eliminates the need for complex fabrication and specialized tools or labs, and which can be economically manufactured and distributed on a global basis.
It is desirable to create a prosthetic device which is immediately fit and aligned on the residual limb during the initial clinical visit and is adjustable and modular to accommodate different residual limb sizes and volume fluctuations that frequently occur in patients after amputation or those with heart failure and renal diseases.
It is desirable to create a prosthetic device which is one size and adjustable to fit many shapes.